Anomalous behavior of the $E_u^1$ infrared-active phonon mode in a Bi${}_{2-x}$Sr${}_x$Se${}_3$ crystal

A. A. Melnikov, K. N. Boldyrev, Yu. G. Selivanov +1

We have studied spectral evolution of the $E_u^1$ phonon line of a topological insulator Bi${}_{2-x}$Sr${}_x$Se${}_3$ with temperature. Unlike the Raman-active phonons, the $E_u^1$ mode…